Exact Analysis Method Of Substructure In Frequency Domain

Substructure is a kind of technique by which the whole system can be parted, then be assembled based on idea "modification and reversion". It can express a very complicated structure by decreasing number of freedom degree. It has proved effective in solving large and complex structures, especially the structures whose substructures are produced in several different manufactures.The history, the development and the presently existing problems of dynamic substructure method, including engineering background, the presentation, the improvement, the advantages and disadvantages of some of Component Mode Synthesis methods are introduced at the beginning of this thesis. But for the present dynamic substructure method, the frequencies and modal shapes of every substructure must be computed. When the reversion of structure is carried out, the method of modal shape truncation should be adopted. This will lead to the lost of parts of the structure information, furthermore, the error should be estimated. In some cases, the influence of high-order modal shapes can not be ignored, which leads a pivotal effect to the vibration of structure. In addition, the programs of the traditional dynamic substructure method are complex by programming and running. Therefore it is unsuitable to be used for the real projects.Based on the above consideration, the method of exact analysis of substructure is developed in frequency domain with hysteresis damping assumption. After considering all information of substructure in frequency domain, the matters which are mentioned above are settled very well. This method is an exact analysis method to calculate structure response, by which the error does not exist any longer (except for the calculation error). On the other hand, the method also absorbs the advantages of the traditional substructure methods and saves much time which programs running needs.Referring to the theory and formula of static substructure method, the basic formula of the method of substructure is derived in frequency domain. The method is applied in lumped mass models (respectively, shear frame model, 6 degrees of freedom, and shear-bend frame model, 12 degrees of freedom), which are parted into two substructures. The earthquake wave is transferred into the frequency domain by FFT, which comes from the earthquake wave EL Centro, the real response of the lumped mass models under the earthquake wave can be gained, including displacement, velocity, and acceleration.In the next chapter, the conception that parallel reversion and sequence reversion in substructure analysis method in frequency domain is put forward there. The frame models are established, whose dynamic degrees of freedom are enlarged through increasing the floor number of these models. Comparing two sequences of response results between substructure method in frequency domain and integral method in frequency domain, the conclusion can be found that the substructure method developed is an exact method for calculating complex and large structure response...